"Of course, the test difficulty depends on what you're doing, and on how you're doing it. I'm constantly asking "How much would I have to screw this up to write an incorrect function that passes these simple tests?" Occasionally the answer is "Not much," so I'll throw the code away and start over. It was probably perfect code, but that's not good enough." [2]

"I often see people saying 'Nobody has produced an invulnerable software system; therefore, nobody will ever produce an invulnerable software system.'

"So it's tempting to incorporate a smaller resolver library into qmail. [...] I'd no longer be able to blame the BIND authors and vendors for the fact that attackers can easily use DNS to steal mail." [From the file "THOUGHTS" of the qmail distribution]